@article {Martin-Diaconescu2009, title = {Effects of hyperconjugation on the electronic structure and photoreactivity of organic sulfonyl chlorides.}, journal = {Inorg. Chem.}, volume = {48}, number = {3}, year = {2009}, month = {feb}, pages = {1038{\textendash}44}, publisher = {The University of British Columbia, Department of Chemistry, Vancouver, British Columbia V6T 1Z1.}, abstract = {The electronic structure of organic sulfonyl compounds of the form RSO(2)G (G = -Cl, -OH, -CH(3)) is investigated to evaluate the effect of aryl R groups on photocleavage of the S-G bond. Sulfur K-edge X-ray absorption spectroscopy (XAS) provides a direct measure of the empty low-lying molecular orbitals in these complexes and, in combination with DFT calculations, a detailed description of the bonding in these compounds. The presence of an aryl group bound to the sulfonyl moiety has a significant impact on the spectroscopy and electronic structure of the site. The analysis suggests that the SCl(sigma*) orbital is significantly affected by mixing with the aryl pi* manifold. This mixing is dependent upon the nature of G and is most pronounced in the sulfonyl chlorides, where the energy of the SCl(sigma*) orbital is lowered by approximately 0.5 eV. The observed mixing is best described as excited-state hyperconjugation of the aryl pi system into the SCl(sigma*) orbital. The magnitude of the effect can be estimated directly from the S K-edge XAS spectra. These results are discussed in relation to the observed photochemistry of RSO(2)Cl, which is significantly enhanced when R = aryl as compared to alkyl substituents.}, keywords = {DFT, ELECTRONS, models, MOLECULAR, molecular structure, Organic Chemicals, Organic Chemicals: chemistry, PHOTOCHEMISTRY, Spectrum Analysis, Sulfinic Acids, Sulfinic Acids: chemistry, sulfur redox, XAS}, issn = {1520-510X}, doi = {10.1021/ic801665f}, url = {http://pubs.acs.org/doi/abs/10.1021/ic50073a047 http://www.ncbi.nlm.nih.gov/pubmed/19132932}, author = {Martin-Diaconescu, Vlad and Kennepohl, Pierre} }